( fis ) 



number of optical organs in the tunica cornea, but all wonderfully 

 minute ; for the fteeple of the new church in our town, the fize of 

 which, and its diftance from my houfe, I have mentioned elfewhere,* 

 when viewed through thefc optical organs, appeared no larger than 

 the point of a very fmall needle. 



Hence, it appears, how greatly thofe perfons are miftaken who 

 fay, that a Beetle is blind ; and how much perfection is to be found 

 in the organs of fight of fo fmall and fo defpifed an animal, to fay 

 nothing of the other parts of its body; but which creature, whoever 

 fees, immediately crufhes with his foot, as loathing the fight of that 

 black creeping thing. 



In the month of Auguft I faw, fitting on a glafs, at the backfide 

 of my houfe, a Fly almoft as large as a bee, which fpecies of Fly, 

 though not very numerous, I obferve every year in the fame place. 



I diflefted the tunica cornea of both eyes of this Fly, and, on ex- 

 amination, I found them to be covered with a great number of 

 wonderfully minute hairs, which did not cover the organs of fight, 

 but were placed in the intermediate fpaces between them. 



Moreover, I took out of the infide of the tunica cornea, that 

 matter or fubftance with which it was filled, in order to examine it 

 by the microfcope, becaufe, till that time, I never could clearly 

 fatisfy myfelf to what end this fubftance was created, and the 

 rather fo, as, upon viewing it, I judged that it confifted of a collec- 

 tion of threads or fibres. Upon fpreading this a little afunder, to ex- 

 amine it more accurately than I had before done, I faw that 

 all thofe particles which I had before confidered as a coUedlion 

 of threads or fibres, were nearly of the fame length, but one of the 

 ends of each fomewhat thicker than the other, and the thicker end 

 rounding at the extremity. 



Upon repeatedly, and more carefully, examining this fpe<ftacle, I 

 was, to a certainty, aflured that every one of that great quantity of 



* See vol. I. Eflay on the Silk-worm, page 62. 



